Optical detection system, blood cell analyzer, and platelet detection method

ABSTRACT

An optical detection system, a blood cell analyzer and a platelet detection method are provided. The optical detection system includes: an optical subsystem, a flow chamber and a first detector; the optical subsystem includes a laser, a front optical assembly including an optical isolator, and a rear optical assembly including a blocking diaphragm. The laser is configured to emit a laser beam; the front optical assembly is configured to perform front optical treatment; the rear optical assembly is disposed downstream of the flow chamber in the propagation direction of the laser beam, and is configured to perform rear optical treatment on the scattered light and the laser beam converged at the blocking diaphragm; and the optical isolator is configured to isolate reflected light that is generated when the laser beam passes through the flow chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/081,757, filed Oct. 27, 2020, for OPTICAL DETECTION SYSTEM, BLOODCELL ANALYZER, AND PLATELET DETECTION METHOD, which is a continuation ofInternational Application No. PCT/CN2019/084509, filed Apr. 26, 2019,which claims priority benefit of Chinese Patent Application No.201810405048.9, filed Apr. 28, 2018, each of which are incorporatedherein by reference.

TECHNICAL FIELD

The disclosure relates to biological inspection technology and, inparticular, to an optical detection system, a blood cell analyzer, and aplatelet detection method.

BACKGROUND ART

The optical detection system in a blood cell analyzer generally uses alaser as a light source, and the laser is susceptible to reflected lightin an optical path and becomes unstable, resulting in amplitude changes,frequency shifts, and/or power peaks, etc.

In practical applications, when power peaks are generated due tounstable oscillation of the laser, they appear in optical forwardsignals as small pulses, and the amplitudes of these small pulses aremuch smaller than that of effective signal pulses generated by whiteblood cell (WBC) particles. Therefore, for WBC optical pulse signalanalysis, the pulse detection threshold value is generally set to begreater than the amplitudes of these interfering small pulses to filterout these pulses. However, to deeply analyze the small signalcharacteristics of the optical pulses to obtain more clinicalinformation, for example, when analyzing platelet (PLT) particles in anoptical channel, these interfering small pulses are confused with smallpulses generated by normal PLT particles, resulting in the inability todifferentiate pulse signals generated by normal PLT from that generatedby the interfering small pulses.

SUMMARY OF THE DISCLOSURE

In view of this, embodiments of the present disclosure provide anoptical detection system, a blood cell analyzer, and a plateletdetection method, which can effectively isolate reflected lightgenerated when laser beams are propagated in an optical path, such thatthe laser can stably output laser beams, and the detection efficiency ofblood cell samples to be tested is improved.

An embodiment of the present disclosure provides a blood cell analyzer,comprising: a sampling part, a reaction part, an optical detectionsystem, an analysis part and an output part, wherein the opticaldetection system comprises an optical subsystem, a flow chamber and afirst detector. The sampling part comprises a sampling needle forcollecting a blood sample and conveying the collected blood sample tothe reaction part. The reaction part comprises a reaction cell and areagent supply component, such that the blood sample reacts with areagent to obtain a test sample solution containing a plurality ofplatelet particles, and the platelet particles are flowed through theflow chamber one by one.

The optical subsystem comprises a laser, a front optical assembly and arear optical assembly, and the front optical assembly comprises anoptical isolator, wherein the laser is configured to emit a laser beam;the flow chamber is configured to allow the platelet particles to passthrough in a line; and the front optical assembly is configured toperform front optical treatment on the laser beam, such that the laserbeam subjected to the front optical treatment is converged in a firstdirection at the platelet particles in the flow chamber, and scatteredlight is thus generated.

The rear optical assembly is disposed downstream of the flow chamberalong the propagation direction of the laser beam, and is configured toperform rear optical treatment on the scattered light, such that thescattered light subjected to the rear optical treatment enters the firstdetector for light intensity detection. The optical isolator isconfigured to isolate reflected light from the laser, wherein thereflected light is generated when the laser beam passes through the flowchamber and the rear optical assembly. The analysis part is configuredto detect platelet particles flowing through the flow chamber accordingto light intensity signals of the scattered light obtained by detectionof the first detector, and thus obtain a detection result correspondingto the platelet particles. The output part is configured to output thedetection result corresponding to the platelet particles.

In the above-mentioned implementation, the optical isolator comprises abeam splitter prism and polarization conversion element which areadhesively connected with each other. The beam splitter prism isconfigured to reflect the S-polarization component of the incident laserbeam and transmit the P-polarization component of the incident laserbeam. The polarization conversion element is configured to change thepolarization state of the P-polarization component transmitted throughthe beam splitter prism such that the P-polarization component ischanged from linearly polarized light into circularly polarized light,as well as to change the polarization state of the circularly polarizedlight after reflection into S-polarized light such that the S-polarizedlight is reflected by the beam splitter prism.

In the above-mentioned implementation, the optical isolator comprises apolarization analyzer and a polarization conversion element which areadhesively connected with each other. The polarization analyzer isconfigured to allow only the P-polarization component of the laser beamto pass through. The polarization conversion element is configured tochange the polarization state of the P-polarization component passingthrough the polarization analyzer, such that the P-polarizationcomponent is changed from linearly polarized light into circularlypolarized light, and to change the polarization state of reflected lightof the circularly polarized light into S-polarized light such that theS-polarized light is isolated by the polarization analyzer.

In the above-mentioned implementation, the optical isolator comprises abandpass filter and a frequency-doubling crystal which are adhesivelyconnected with each other. The bandpass filter is configured to allowthe laser beam with a wavelength λ to pass through. Thefrequency-doubling crystal is configured to perform frequency doublingon the laser beam passing through the bandpass filter and performfrequency doubling again on reflected light of the frequency-doubledlaser beam, such that the reflected light is filtered out by thebandpass filter.

In the above-mentioned implementations, the front optical assemblyfurther comprises a collimating lens. The collimating lens is disposedbetween the laser and the optical isolator along the propagationdirection of the laser beam, and is configured to collimate the laserbeam to make the laser beam become a parallel beam.

In the above-mentioned implementations, the rear optical assemblyfurther comprises a blocking diaphragm. The front optical assembly isfurther configured to perform front optical treatment on the laser beamsuch that the laser beam subjected to the front optical treatment isconverged at the blocking diaphragm in a second direction.

In the above-mentioned implementations, the front optical assemblyfurther comprises a first light converging element and a second lightconverging element. The first light converging element is configured toperform first focusing on the laser beam, such that the laser beam isconverged in the first direction at a detection area of the flowchamber, and scattered light is generated. The second light convergingelement is configured to perform second focusing on the laser beam suchthat the laser beam is converged in a second direction at the blockingdiaphragm comprised by the rear optical assembly.

In the above-mentioned implementations, the rear optical assemblyfurther comprises a third converging element and an aperture diaphragm.The third converging element is configured to perform third focusing onthe scattered light such that the scattered light is converged at theaperture diaphragm and enters the first detector via the aperture of theaperture diaphragm.

In the above-mentioned implementations, the optical detection systemfurther comprises a second detector and/or a fluorescence detector. Thesecond detector is configured to perform light intensity detection onthe scattered light which forms an angle within a preset angle range(for example, 60° to 120°) with the propagation direction of the laserbeam. The fluorescence detector is configured to detect fluorescencegenerated by the platelet particles.

In the above-mentioned implementations, the analysis part is furtherconfigured to detect the platelet particles in the flow chamberaccording to at least one of the following information and thus obtain adetection result corresponding to the platelet particles: lightintensity signals of the scattered light obtained by detection of thesecond detector; and fluorescence intensity signals obtained bydetection of the fluorescence detector.

In the above-mentioned implementations, the reaction part is furtherconfigured to perform hemolysis treatment on the collected blood sample,such that red blood cells in the blood sample are lysed to obtain a testsample solution containing a plurality of platelet particles.

In the above-mentioned implementations, the second direction isperpendicular to the flow direction of the platelet particles; and thefirst direction is the same as the flow direction of the plateletparticles.

In the above-mentioned implementations, the included angle between thepropagation direction of the laser beam and the light incident surfaceof the flow chamber is a non-perpendicular angle.

In the above-mentioned implementations, the laser beam is P-linearlypolarized light.

An embodiment of the present disclosure further includes a plateletdetection method applied to a blood cell analyzer comprising an opticaldetection system, wherein the optical detection system comprises alaser, a front optical assembly comprising an optical isolator, a rearoptical assembly, a flow chamber, and a first detector; the methodcomprises: providing a test sample solution containing platelets; makingplatelet particles in the test sample solution pass through thedetection area of the flow chamber one by one; performing front opticaltreatment on a laser beam emitted by the laser by using the frontoptical assembly such that the laser beam subjected to the front opticaltreatment is converged at a detection area of the flow chamber in afirst direction, and scattered light is generated when the plateletparticles pass through the detection area; performing rear opticaltreatment on the scattered light by using the rear optical assembly suchthat the scattered light subjected to the rear optical treatment entersthe first detector, wherein reflected light generated when the laserbeam passes through the flow chamber is isolated by the opticalisolator; and performing light intensity detection on the incidentscattered light by using the first detector to obtain a first detectionresult so as to identify the platelet particles based on the firstdetection result.

In the above-mentioned implementation, the method further comprises:performing hemolysis treatment on the collected blood sample, such thatred blood cells in the blood sample are lysed to obtain a test samplesolution containing a plurality of platelet particles. Preferably, inthe test sample solution, the scattered light characteristics offragments obtained by lysing red blood cells are significantly differentfrom that of the platelet particles.

In the above-mentioned implementations, the method further comprises:performing front optical treatment on the laser beam by using the frontoptical assembly such that the laser beam subjected to the front opticaltreatment is converged at the blocking diaphragm included by the rearoptical assembly in a second direction.

In the above-mentioned implementations, the blood cell analyzer furthercomprises a second detector; correspondingly, the method furthercomprises: performing light intensity detection on the scattered lightwhich forms an angle within a preset angle range with the propagationdirection of the laser beam to obtain a second detection result, therebyidentifying the platelet particles based on the first detection resultand the second detection result.

In the above-mentioned implementations, the blood cell analyzer furthercomprises a fluorescence detector; correspondingly, the method furthercomprises: performing fluorescence staining treatment on the plateletparticles in the test sample solution; further generating fluorescencewhen the platelet particles in the test sample solution pass through thedetection area; and configuring the fluorescence detector to detect thefluorescence generated by the platelet particles to obtain a thirddetection result, thereby identifying the platelet particles based onthe first detection result and the third detection result.

In the above-mentioned implementations, the blood cell analyzer furthercomprises a second detector and a fluorescence detector;correspondingly, the method further comprises: performing fluorescencestaining treatment on the platelet particles in the test samplesolution; further generating fluorescence when the platelet particles inthe test sample solution pass through the detection area; configuringthe second detector to perform light intensity detection on thescattered light which forms an angle within a preset angle range withthe propagation direction of the laser beam to obtain a second detectionresult; configuring the fluorescence detector to detect fluorescencegenerated by the platelet particles to obtain a third detection result;identifying the platelet particles according to the first detectionresult and the third detection result; identifying white blood cellparticles, and/or counting white blood cells, and/or differentiatingwhite blood cells to obtain white blood cell subpopulations at leastincluding monocytes, lymphocytes, and neutrophils, according to thesecond detection result and the third detection result.

An embodiment of the present disclosure further provides an opticaldetection system, comprising an optical subsystem, a flow chamber, and afirst detector. The optical subsystem comprises a laser, a front opticalassembly comprising an optical isolator, and a rear optical assemblycomprising a blocking diaphragm, wherein the laser is configured to emita laser beam. The front optical assembly is configured to perform frontoptical treatment on the laser beam, and the laser beam subjected to thefront optical treatment is converged in a second direction at theblocking diaphragm and is converged in a first direction at a blood cellsample to be tested in the flow chamber, and scattered light is thusgenerated. The rear optical assembly is disposed downstream of the flowchamber along the propagation direction of the laser beam, and isconfigured to perform rear optical treatment on the scattered light andthe laser beam which is converged at the blocking diaphragm, such thatthe scattered light subjected to the rear optical treatment enters thefirst detector for light intensity detection. The optical isolator isconfigured to isolate reflected light generated when the laser beampasses through the flow chamber and the rear optical assembly.

In the above-mentioned implementation, the optical isolator comprises abeam splitter prism and polarization conversion element which areadhesively connected with each other. The beam splitter prism isconfigured to reflect the S-polarization component of the incident laserbeam and transmit the P-polarization component of the incident laserbeam. The polarization conversion element is configured to change thepolarization state of the P-polarization component transmitted throughthe beam splitter prism such that the P-polarization component ischanged from linearly polarized light into circularly polarized light,as well as to change the polarization state of the circularly polarizedlight after reflection into S-polarized light such that the S-polarizedlight reflected by the beam splitter prism.

In the above-mentioned implementation, the optical isolator comprises apolarization analyzer and a polarization conversion element which areadhesively connected with each other. The polarization analyzer isconfigured to allow only the P-polarization component of the laser beamto pass through. The polarization conversion element is configured tochange the polarization state of the P-polarization component passingthrough the polarization analyzer, such that the P-polarizationcomponent is changed from linearly polarized light into circularlypolarized light, and to change the polarization state of reflected lightof the circularly polarized light into S-polarized light such that theS-polarized light isolated by the polarization analyzer.

In the above-mentioned implementations, when the laser beam is incidentto the optical isolator perpendicularly, the reflectivity of the firstincident surface of the beam splitter prism is not greater than 0.5%.

In the above-mentioned implementations, the optical isolator comprises abandpass filter and a frequency doubling crystal which are adhesivelyconnected with each other. The bandpass filter is configured to allowthe laser beams with a wavelength λ to pass through. Thefrequency-doubling crystal is configured to perform frequency doublingon the laser beam passing through the bandpass filter and performfrequency doubling again on reflected light of the frequency-doubledlaser beam, such that the reflected light is filtered out by thebandpass filter.

In the above-mentioned implementations, the front optical assemblyfurther comprises a collimating lens. The collimating lens is disposedbetween the laser and the optical isolator along the propagationdirection of the laser beam, and is configured to collimate the laserbeam to make the laser beam become a parallel beam.

In the above-mentioned implementations, the front optical assemblyfurther comprises a first light converging element and a second lightconverging element. The first light converging component is configuredto perform first focusing on the laser beam such that the laser beam isconverged in the first direction at the blood cell sample to be testedin the flow chamber, and scattered light is generated. The second lightconverging element is configured to perform second focusing on the laserbeam such that the laser beam is converged in the second direction atthe blocking diaphragm.

In the above-mentioned implementations, the rear optical assemblyfurther comprises a third converging element and an aperture diaphragm.The third converging component is configured to perform third focusingon the scattered light such that the scattered light is converged at theaperture diaphragm and enters the first detector via the aperture of theaperture diaphragm.

In the above-mentioned implementations, the optical detection systemfurther comprises a second detector and a fluorescence detector. Thesecond detector is configured to perform light intensity detection thescattered light which forms an angle within a preset angle range (forexample, 60° to 120°) with the propagation direction of the laser beam;and the fluorescence detector is configured to perform fluorescencedetection on fluorescence generated by the blood cell sample to betested.

In the above-mentioned implementations, the second direction isperpendicular to the flow direction of the blood cell sample to betested; and the first direction is the same as the flow direction of theblood cell sample to be tested.

In the above-mentioned implementations, the optical isolator has anoptical isolation degree not smaller than 30 db.

In the above-mentioned implementations, the blocking diaphragm has alight collection angle of 1-10°.

In the above-mentioned implementations, the laser beam has a wavelengthof 630 nm to 640 nm.

In the above-mentioned implementations, the laser beam is P-linearlypolarized light.

By applying the optical detection system, the blood cell analyzer andthe platelet detection method of the above-mentioned embodiments of thepresent disclosure, reflected light generated when a laser beam ispropagated in an optical path can be commendably isolated, such that thelaser can stably output a laser beam, thereby avoiding small pulsesoccurring due to power peaks generated when the reflected light entersthe laser, also avoiding confusion between those interfering smallpulses and small pulses generated by platelet particles, andsignificantly improving the detection precision of the blood cellanalyzer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic structure diagram I of an opticaldetection system provided by an embodiment of the present disclosure;

FIG. 2 illustrates a schematic structure diagram II of an opticaldetection system provided by an embodiment of the present disclosure;

FIG. 3A-FIG. 3C illustrate a principle diagrams of three types ofoptical isolators provided by embodiments of the present disclosure,respectively;

FIG. 4 illustrates a schematic diagram of a first incident surface of anoptical isolator provided by an embodiment of the present disclosure;

FIG. 5 illustrates a light converging schematic diagram of a secondcylindrical lens provided by an embodiment of the present disclosure;

FIG. 6 illustrates a front view of a blocking diaphragm provided by anembodiment of the present disclosure;

FIG. 7 illustrates a schematic structure diagram of a blood cellanalyzer provided by an embodiment of the present disclosure;

FIG. 8 illustrates a schematic structure diagram III of an opticaldetection system provided by an embodiment of the present disclosure;and

FIG. 9 illustrates a schematic structure diagram IV of an opticaldetection system provided by an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure will be further described below in detail incombination with the accompanying drawings and the embodiments. Itshould be understood that the embodiments provided herein are only forexplaining the present disclosure, but not for limiting the presentdisclosure. In addition, the embodiments provided below are a part ofembodiments for implementing the present disclosure, but not allembodiments. And in a non-conflict case, the technical solutionsrecorded in the embodiments of the present disclosure can be implementedin an arbitrary combination way.

It should be noted that, in the embodiments of the present disclosure,the term ‘include’, ‘comprise’, or any other variant is intended tocover a non-exclusive meaning, such that a method or a device comprisinga series of elements not only comprises expressly recorded elements butalso comprises other elements not expressly listed, or further comprisesinherent elements for implementing the method or device. Without furtherrestrictions, the elements defined by the sentence ‘comprising a . . . ’do not exclude other relevant elements (for example, steps in a methodor units in a device, herein the units may be some circuits, someprocessors, some programs, or software, etc.) which are furthercomprised in the method or device comprising the elements.

It should be noted that, the terms ‘first/second/third/’ related to theembodiments of the present disclosure are only for distinguishingsimilar objects rather than representing specific sequence of the aimedobjects, and it can be understood that ‘first/second/third/’ areinterchangeable in a specific sequence or a precedence order underallowable conditions. It should be understood that the objectsdistinguished by ‘first/second/third/’ are interchangeable under properconditions such that the embodiments of the present disclosure describedherein can be implemented in a sequence excluding those shown in thedrawings or described herein.

During research, the inventors have discovered that, in order to preventreflected light from being fed back to the laser, a magneto-opticaldevice based on the Faraday effect can be used as an optical isolatorand placed in the optical path. This isolator has a relatively largemechanical size and generally can only be placed outside a light sourceassembly, while the light beam outside the light source assembly isnon-parallel light, and when non-parallel light enters the opticalisolator, the optical isolation effect of the optical isolator will beseriously weakened. Therefore, this solution has the disadvantages oflarge size, high cost, and poor isolation effect.

In an embodiment of the present disclosure, the optical detection systemcomprises an optical subsystem, a flow chamber and a first detector, andthe optical subsystem comprises a laser, a front optical assemblycomprising an optical isolator, and a rear optical assembly comprising ablocking diaphragm, wherein the laser is configured to emit a laserbeam; the front optical assembly is configured to perform front opticaltreatment on the laser beam, such that the laser beam subjected to thefront optical treatment is converged at the blocking diaphragm in asecond direction and is converged in a first direction at a blood cellsample to be tested in the flow chamber, and scattered light is thusgenerated; the rear optical assembly is disposed downstream of the flowchamber along the propagation direction of the laser beam, and isconfigured to perform rear optical treatment on the scattered light andthe laser beam which is converged at the blocking diaphragm, such thatthe scattered light subjected to the rear optical treatment enters thefirst detector for light intensity detection; and the optical isolatoris configured to isolate reflected light generated when the laser beampasses through the flow chamber and the rear optical assembly.

An optical detection system provided by an embodiment of the presentdisclosure will be described in detail.

FIG. 1 is a schematic structure diagram I of an optical detection systemprovided by an embodiment of the present disclosure, and FIG. 2 is aschematic structure diagram II of an optical detection system 200provided by an embodiment of the present disclosure. With reference toFIG. 1 and FIG. 2 , the optical detection system 200 provided by theembodiment of the present disclosure comprises an optical subsystem 1, aflow chamber 2, and a first detector 3.

The optical subsystem 1 comprises a laser 11, a front optical assembly12 comprising an optical isolator 121, and a rear optical assembly 13comprising a blocking diaphragm 131, wherein

the laser 11 is configured to emit a laser beam; the front opticalassembly 12 is configured to perform front optical treatment on thelaser beam, such that the laser beam subjected to the front opticaltreatment is converged at the blocking diaphragm 131 in a seconddirection, and is converged in a first direction at a blood cell sampleto be tested in the flow chamber 2, and scattered light is thusgenerated; the rear optical assembly 13 is disposed downstream of theflow chamber 2 along the propagation direction of the laser beam, and isconfigured to perform rear optical treatment on the scattered light andthe laser beam converged at the blocking diaphragm 131, such that thescattered light subjected to the rear optical treatment enters the firstdetector 3 for light intensity detection; and the optical isolator 121is configured to isolate reflected light generated when the laser beampasses through the flow chamber and the rear optical assembly.

Next, the laser 11 in the optical subsystem will be described. In anembodiment, the laser 11 is a semiconductor laser. In a practicalimplementation, the laser 11 may be a P-linearly polarization laser. Inpractical applications, the wavelength of the laser beam emitted by thelaser determines the design of the main parameters of the optical path,such as model selection of a lens, the selection of signal collectionangle and the like, and the wavelength of the laser beam is also relatedto the reagents such as fluorescence dyes used in the detection. In anembodiment, the wavelength of laser beam emitted by the laser 11 iswithin 630 nm to 640 nm.

Next, each part of the front optical assembly 12 in the opticalsubsystem will be described. In an embodiment, the optical isolator 121in the front optical assembly 12 comprises a beam splitter prism and apolarization conversion element which are adhesively connect with eachother. The beam splitter prism is configured to reflect theS-polarization component of the incident laser beam and transmit theP-polarization component of the incident laser beam. The polarizationconversion element is configured to change the polarization state of theP-polarization component transmitted through the beam splitter prismsuch that the P-polarization component is changed from linearlypolarized light into circularly polarized light, as well as to changethe polarization state of the circularly polarized light afterreflection into S-polarized light such that the S-polarized light isreflected by the beam splitter prism.

The polarization conversion element is a quarter wave plate, which istaken as an example, as shown in FIG. 3A. FIG. 3A is a principle diagramof an optical isolator provided by an embodiment of the presentdisclosure. When laser beam L (TM mold) enters the beam splitter prism35 perpendicularly, the P-polarized light 31 (namely the polarizationcomponent parallel to the plane of the drawing) in the laser beam L canpass through the beam splitter prism 35, while the S-polarized light 32(namely the polarization component perpendicular to the plane of thedrawing) in the laser beam L is reflected by a 45-degree bevel of thebeam splitter prism 35. Afterwards, the P-polarized light 31 passesthrough the quarter wave plate 36, and the polarization state of theP-polarized light 31 passing through the quarter wave plate 36 ischanged from linearly polarized light into circularly polarized light33; the reflected light (reflected light reflected by the downstreamoptical path 37) of the circularly polarized light 33 passes through thequarter wave plate 36 again and the polarization state is changed fromcircularly polarized light into S-polarized light 34, and theS-polarized light 34 will be reflected by the 45-degree bevel of thebeam splitter prism 35 without being fed back to the laser, therebyrealizing the isolation of the reflected light in the optical path.

In practical applications, when the laser beam is perpendicularlyincident to the optical isolator, the reflectivity of the first incidentsurface of the beam splitter prism is not greater than 0.5%, or notgreater than 0.1%, or not greater than 0.05%. The first incident surfaceis shown in FIG. 4 . FIG. 4 is a schematic diagram of the first incidentsurface of an optical isolator provided by an embodiment of the presentdisclosure, wherein the reference number 41 represents the firstincident surface. In a practical implementation, the light reflectivityof the first incident surface can be achieved by the coating design andprocess of the first incident surface.

In an embodiment, as shown in FIG. 3B, the optical isolator 121 may alsocomprise a polarization analyzer and a polarization conversion elementwhich are adhesively connected with each other. The polarizationanalyzer is configured to allow only the P-polarization component of thelaser beam to pass through. The polarization conversion element isconfigured to change the polarization state of the P-polarizationcomponent passing through the polarization analyzer such that theP-polarization component is changed from linearly polarized light intocircularly polarized light, as well as to change the polarization stateof reflected light of the circularly polarized light after reflectioninto S-polarized light such that the S-polarized light is isolated bythe polarization analyzer.

As an example, the polarization conversion element is a magneto-opticalcrystal. When the laser beam enters the polarization analyzer, only theP-polarized light in the laser beam can pass through the polarizationanalyzer. After the P-polarized light passing through the polarizationanalyzer enters the magneto-optical crystal, the polarization state ofthe P-polarized light passing through the magneto-optical crystal ischanged, and the polarization direction of the P-polarized light isrotated by 45°. The reflected light formed after the polarized light isreflected by the downstream optical path passes through themagneto-optical crystal again, and the polarization direction is rotatedby 45° again, thereby forming S-polarized light perpendicular to thepolarization state of the original P-polarized light such that theS-polarized light is isolated by the polarization analyzer without beingfed back to the laser.

In practical applications, the polarization conversion element may alsobe a rotary optical crystal. In practical applications, the beamsplitter prism and the polarization analyzer can be combined with anyone of the quarter wave plate, the magneto-optical crystal and therotary optical-crystal to achieve the isolation of the reflected lightin the optical path.

In an embodiment, as shown in FIG. 3C, the optical isolator 121comprises a bandpass filter and a frequency doubling crystal which areadhesively connected with each other. The bandpass filter is configuredto allow the laser beam with a wavelength λ to pass through. Thefrequency-doubling crystal is configured to perform frequency doublingon the laser beam passing through the bandpass filter and performfrequency doubling again on reflected light of the frequency-doubledlaser beam, such that the reflected light is filtered out by thebandpass filter.

In an embodiment, the optical isolator has an optical isolation degreenot smaller than 30 db.

In an embodiment, the front optical assembly 12 further comprises acollimating lens 122. The collimating lens 122 is disposed between thelaser 11 and the optical isolator 121 along the propagation direction(the direction of the optical axis) of the laser beam, and is configuredto collimate the laser beam to make the laser beam become a parallelbeam. In an embodiment, the front optical assembly 12 further comprisesa first light converging element 123 and a second light convergingelement 124. The first light converging element 123 is configured toperform first focusing on the laser beam such that the laser beam isconverged in the first direction at the blood cell sample to be testedin the flow chamber, and the scattered light is thus generated. Thesecond light converging element 124 is configured to perform secondfocusing on the laser beam such that the laser beam is converged at theblocking diaphragm 131 in the second direction.

In practical applications, the second direction is the transversedirection, namely a direction perpendicular to the flow direction of theblood cell sample to be tested; and the first direction is thelongitudinal direction, namely a direction the same as the flowdirection of the blood cell sample to be tested. In practicalapplications, the first light converging element 123 and the secondlight converging element 124 may be implemented by cylindrical lenseswith different optical parameters (such as focal length, etc.), forexample, the first light converging element 123 is implemented by afirst cylindrical lens, and the second light gathering component 124 isimplemented by a second cylindrical lens.

The second light converging element 124 is a second cylindrical lens,which is taken as an example for description, as shown in FIG. 5 . FIG.5 is a light converging schematic diagram of a second cylindrical lensprovided by an embodiment of the present disclosure. The laser beampasses through the second cylindrical lens and is not treated in thelongitudinal direction by the second cylindrical lens; the laser beampassing through the second cylindrical lens is compressed in thetransverse direction and is focused in the transverse direction(perpendicular to the flow direction of the blood cell sample to betested); and the laser beam is focused at the blocking diaphragm in theembodiment of the present disclosure.

Next, each part of the rear optical assembly 13 will be described, asshown in FIG. 6 . FIG. 6 is a front view of a blocking diaphragmprovided by an embodiment of the present disclosure. The laser beamirradiated on the blood cell sample in the flow chamber is scattered,and the generated scattered light is collected by the blockingdiaphragm. In a practical implementation, the blocking diaphragm is usedto restrict the collection angle of low-angle scattering signals and theblocking diaphragm is also used to stop the laser beam converged at theblocking diaphragm in the second direction. In an embodiment, the lightcollection angle of the blocking diaphragm may be 1-10°.

In an embodiment, the rear optical assembly 13 further comprises a thirdconverging element 132 and an aperture diaphragm 133. The thirdconverging element 132 is configured to perform third focusing on thescattered light such that the scattered light is converged at theaperture diaphragm and enters the first detector via the aperture of theaperture diaphragm, for light intensity detection.

In an embodiment, the third converging element may be one of thefollowing:

-   -   a lens assembly including at least one plano-convex lens and at        least one biconvex lens;    -   a lens assembly including at least two plano-convex lenses;    -   a lens assembly including at least two biconvex lenses;    -   a lens assembly including at least two spherical lenses; and    -   an aspherical lens.

In an embodiment, the optical detection system further comprises asecond detector 4 and a fluorescence detector 5. The second detector isdisposed in a direction which forms an angle within a preset angle rangewith the propagation direction of the laser beam, and is configured toperform light intensity detection on the scattered light which forms anangle within the preset angle range with the propagation direction ofthe laser beams. The fluorescence detector is disposed in a directionwhich forms an angle within a preset angle range with the propagationdirection of the laser beam, and is configured to perform fluorescencedetection on fluorescence generated by the blood cell sample to betested.

Next, a blood cell analyzer provided by an embodiment of the presentdisclosure will be described, and FIG. 7 is a schematic structurediagram of a blood cell analyzer 700 provided by an embodiment of thepresent disclosure. The blood cell analyzer 700 comprises a firsthousing 100, a second housing 200, a sampling part 10, a reaction part30, an optical detection system 50, an analysis part 70 and an outputpart 90. In practical applications, the output part 90 may be a userinterface. In this embodiment, the optical detection system 50 and theanalysis part 70 are disposed inside the second housing 200, and aredisposed on two sides of the second housing 200, respectively. Thereaction part 30 is disposed inside the first housing 100, and theoutput part 90 and the sampling part 10 are disposed on outer surface ofthe first housing 100.

The optical detection system 50 may include an optical subsystem, a flowchamber and a first detector. The sampling part 10 comprises a samplingneedle for collecting a blood sample and conveying the collected bloodsample to the reaction part. The reaction part 30 comprises a reactioncell and a reagent supply component and provides a reaction place forthe blood sample to react with a reagent to obtain a test samplesolution containing a plurality of platelet particles. The reaction partfurther comprises a pipeline and a drive component, such as an injector,an air pump, etc., such that the platelet particles are flowed throughthe flow chamber one by one.

The optical subsystem comprises a laser, a front optical assembly and arear optical assembly, and the front optical assembly comprises anoptical isolator, wherein the laser comprises a light source and is usedto emit a laser beam; the flow chamber allows platelet particles to passthrough in a line; the front optical assembly is configured to performfront optical treatment on the laser beam, and the laser beam subjectedto the front optical treatment is converged in a first direction at theplatelet particles in the flow chamber, and scatter light is thusgenerated; the rear optical assembly is disposed downstream of the flowchamber along the propagation direction of the laser beam, and isconfigured to perform rear optical treatment on the scattered light,such that the scattered light subjected to the rear optical treatmententers the first detector for light intensity detection; the opticalisolator is configured to isolate reflected light from the laser;wherein the reflected light is generated when the laser beam passesthrough the flow chamber and the rear optical assembly; the analysispart 70 is configured to detect platelet particles flowing through theflow chamber according to light intensity signals of the scattered lightobtained by detection of the first detector to obtain a detection resultcorresponding to the platelet particles; the output part 90 isconfigured to output the detection result corresponding to the plateletparticles.

Next, each part included by the optical detection system 50 of the bloodcell analyzer 700 will be described.

FIG. 8 is a schematic structure diagram of an optical detection systemprovided by an embodiment of the present disclosure. As shown in FIG. 8, the optical detection system provided by the embodiment of the presentdisclosure comprises a laser 71, a front optical assembly 72, a flowchamber 73, and a rear optical assembly 74, a forward detector 75, aside detector 76, and a fluorescence detector 77.

In practical applications, the platelet particles pass through the flowchamber and are detected (such as detected in terms of light intensity),counted, etc. In this embodiment, the flow direction of plateletparticles is a direction perpendicular to the plane of the drawing, andthe propagation direction of the laser beam emitted by the laser 71 is adirection parallel to the plane of drawing.

In a practical implementation, the laser 71 is a P-linearly polarizationlaser, and the wavelength of the laser beam emitted by the laser 71 iswithin 630 nm to 640 nm.

As shown in FIG. 8 , the front optical assembly 72 comprises acollimating lens 721, an optical isolator 722, a first cylindrical lens723 and a second cylindrical lens 724 that are sequentially disposed inthe propagation direction of the laser beam. The rear optical assembly74 comprises a blocking diaphragm 741, a plano-convex lens 742, abiconvex lens 743 and an aperture diaphragm 744 that are sequentiallydisposed in the propagation direction of the laser beam.

The laser beam emitted by the laser 71 is collimated by the collimatinglens 721 to become a parallel laser beam, then passes through theoptical isolator 722, and is focused at the center of the flow chamber73 in the longitudinal direction (perpendicular to the plane of drawing)by the first cylindrical lens 723 to form a detection light spot. Theincluded angle between the propagation direction of the laser beam andthe light incident surface of the flow chamber is a right angle. Thelaser beam focused at the flow chamber is irradiated on the plateletparticles in the flow chamber and is thus scattered. After beingcompressed in the longitudinal direction by the first cylindrical lens723, the size of the laser beam in the longitudinal direction is matchedwith that of the platelet particles. The laser beam passing through thefirst cylindrical lens 723 enters the second cylindrical lens 724, andis compressed in the transverse direction (parallel to the plane ofdrawing), and is converged in the transverse direction at the blockingdiaphragm 741.

Wherein the scattered light generated by the platelet particlesirradiated in the flow chamber is collected by the blocking diaphragmsuch that the scattered light is focused by a lens assembly consistingof the plano-convex lens 742 and the lenticular lens 743, then convergedat the aperture diaphragm 744 and enters the forward detector 75 via theaperture of the aperture diaphragm 744 so as to be detected in terms offorward light signal intensity by the forward detector 75.

In practical applications, as shown in FIG. 8 , the side detector 76 andthe fluorescence detector 77 are disposed along a directionperpendicular to the propagation direction of the laser beam, whereinthe side detector 76 is configured to perform light intensity detectionon the scattered light perpendicular to the propagation direction of thelaser beam, and the fluorescence detector 77 is disposed along adirection perpendicular to the propagation direction of the laser beamand is configured to perform fluorescence detection on the scatteredlight.

In a practical implementation, the laser beam emitted by the laser 71will be reflected when propagating in the optical path shown in FIG. 8 ,and the optical isolator 722 is configured to isolate the reflectedlight generated by the laser beam emitted by the laser 71 when the laserbeam propagates in the optical path.

In an embodiment, the optical isolator 722 comprises a beam splitterprism and a quarter wave plate which are adhesively connected with eachother. The beam splitter prism is configured to reflect theS-polarization component of the incident laser beam and transmit thepolarization-polarization component of the incident laser beam. Thequarter wave plate is configured to change the polarization state of theP-polarization component transmitted through the beam splitter prismsuch that the P-polarization component is changed from linearlypolarized light into circularly polarized light, as well as to changethe polarization state of the circularly polarized light afterreflection into S-polarized light such that the S-polarized light isreflected by the beam splitter prism.

When laser beam enters the beam splitter prism perpendicularly, theP-polarized light (namely the polarization component parallel to theplane of the drawing) in the laser beam can pass through the beamsplitter prism, while the S-polarized light (namely the polarizationcomponent perpendicular to the plane of the drawing) in the laser beamis reflected by a 45-degree bevel of the beam splitter prism;afterwards, the P-polarized light passes through the quarter wave plate,and the polarization state of the P-polarized light passing through thequarter wave plate is changed from linearly polarized light intocircularly polarized light; the reflected light (reflected lightreflected by the downstream optical path) of the circularly polarizedlight passes through the quarter wave plate again, and the polarizationstate is change from the circularly polarized light to S-polarizedlight; and the S polarized light will be reflected by the 45-degreebevel of the beam splitter prism without being fed back to the laser,thereby realizing the isolation of the reflected light in the opticalpath.

In practical applications, when the laser beam enters the opticalisolator perpendicularly, the reflectivity of the first incident surfaceof the beam splitter prism is not greater than 0.5%. Herein, the firstincident surface is shown in FIG. 4 . FIG. 4 is a schematic diagram of afirst incident surface of an optical isolator provided by an embodimentof the present disclosure, wherein the surface represented by thereference number 41 is the first incident surface. In a practicalimplementation, the light reflectivity of the first incident surface canbe achieved by the coating design and process of the first incidentsurface.

In an embodiment, the optical isolator 121 may also comprise apolarization analyzer and a polarization conversion element which areadhesively connected with each other. The polarization analyzer isconfigured to allow only the P-polarization component of the laser beamto pass through. The magneto-optical crystal is configured to change thepolarization state of the P-polarization component passing through thepolarization analyzer such that the polarization direction of theP-polarization component is rotated by 45°. The reflected light formedafter the polarized light is reflected by the downstream optical pathpasses through the magneto-optical crystal again, and the polarizationdirection is rotated by 45° again, thereby forming S-polarized lightperpendicular to the polarization state of the original P-polarizedlight such that the S-polarized light is isolated by the polarizationanalyzer.

When the laser beam enters the polarization analyzer, only theP-polarized light in the laser beam can pass through the polarizationanalyzer, the P-polarized light passing through the polarizationanalyzer enters the magneto-optical crystal, the polarization state ofthe P-polarized light passing through the magneto-optical crystal ischanged, and the polarization direction of the P-polarized light isrotated by 45°. The reflected light formed after the polarized light isreflected by the downstream optical path passes through themagneto-optical crystal again, and the polarization direction is rotatedby 45° again, thereby forming S-polarized light perpendicular to thepolarization state of the original P-polarized light such that theS-polarized light is isolated by the polarization analyzer without beingfed back to the laser.

In an embodiment, the optical isolator may further comprise a bandpassfilter and a frequency doubling crystal which are adhesively connectedwith each other. The bandpass filter is configured to allow the laserbeam with a wavelength λ to pass through. The frequency-doubling crystalis configured to perform frequency doubling on the laser beam passingthrough the bandpass filter and perform frequency doubling again onreflected light of the frequency-doubled laser beam, such that thereflected light is filtered out by the bandpass filter.

In an embodiment, the optical isolator has an optical isolation degreenot smaller than 30 db.

In an embodiment, the included angle between the propagation directionof the laser beam and the light incident surface of the flow chamber maybe a non-perpendicular angle, namely the position of the flow chamber inthe above-mentioned embodiments is deflected by a certain angle in thex-y plane, namely in the plane of drawing such that the flow chamber isobliquely disposed. FIG. 9 is a schematic structure diagram of anoptical detection system provided by an embodiment of the presentdisclosure. As shown in FIG. 9 , the included angle θ between thepropagation direction of the laser beam and the light incident surfaceof the flow chamber is an acute angle. In an embodiment, the angle θranges from 80° to 90°. Thus, when the laser beam irradiates the insideof the flow chamber and after the light beam is reflected on the innersurface of the flow chamber, the reflected light is deviated from theoptical axis (the propagation direction of laser beam), thereby reducingthe luminous flux of the reflected light entering the laser. Thoseskilled in the art can understand that the angle θ is applicable to thepresent application as long as it would not cause the light reflected onthe light incident surface of the flow chamber to enter the front lightmodule. Through in-depth researches, it was found that although theoblique placement of the flow chamber may cause deviation of the opticalpath of forward scattered light and change of the collection angles offluorescence and side scattered light, by further in-depth researches,it was found that it is possible to compensate for the influence of theforward scattered light by adjusting the position of the rear opticalassembly in the optical path, and meanwhile, it has been proved througha large number of research experiments this is acceptable for thedetection of the fluorescence and side scattered light, withoutaffecting final detection results.

In the above-mentioned embodiments of the present disclosure, plateletparticles are relatively small and generate small pulses when flowingthrough the flow chamber, as the reflected light generated by the laserbeam when propagating in the optical path can be commendably isolated bythe optical isolator in the optical detection system in theabove-mentioned blood cell analyzer, the laser can stably output a laserbeam, thereby avoiding small pulses occurring due to power peaksgenerated when the reflected light enters the laser, also avoidingconfusion between the interfering small pulses and the small pulsesgenerated by platelet particles, and greatly improving the detectionprecision.

An embodiment of the present disclosure also provides a plateletdetection method applied to the above-mentioned blood cell analyzercomprising an optical detection system, wherein the optical detectionsystem comprises a laser, a front optical assembly comprising an opticalisolator, a rear optical assembly, a flow chamber and a first detector.The method comprises: providing a test sample solution containingplatelets; making platelet particles in the test sample solution passthrough a detection area of the flow chamber one by one; performingfront optical treatment on a laser beam emitted by the laser by usingthe front optical assembly such that the laser beam subjected to thefront optical treatment is converged at the detection area of the flowchamber in a first direction and scattered light is generated when theplatelet particles pass through the detection area; performing rearoptical treatment on the scattered light by using the rear opticalassembly such that the scattered light subjected to the rear opticaltreatment enters the first detector, wherein reflected light generatedwhen the laser beam passes through the flow chamber and the rear opticalassembly is isolated by the optical isolator; and performing lightintensity detection on the incident scattered light by using the firstdetector to obtain a first detection result so as to identify theplatelet particles based on the first detection result.

In an embodiment, the method further comprises: performing hemolysistreatment on the collected blood sample, such that red blood cells inthe blood sample are lysed to obtain a test sample solution containing aplurality of platelet particles.

In an embodiment, the method further comprises: performing front opticaltreatment on the laser beam by using the front optical assembly suchthat the laser beam subjected to the front optical treatment isconverged at a blocking diaphragm included by the rear optical assemblyin a second direction.

In an embodiment, the blood cell analyzer further comprises a seconddetector; correspondingly, the method further comprises: performinglight intensity detection on the scattered light which forms an anglewithin a preset angle range with the propagation direction of the laserbeam to obtain a second detection result, thereby identifying theplatelet particles based on the first detection result and the seconddetection result.

In an embodiment, the blood cell analyzer further comprises afluorescence detector; correspondingly, the method further comprises:performing staining treatment on the platelet particles in the testsample solution by using a specific fluorescence dye, wherein thespecific fluorescence dye may be at least one of a membrane dye and amitochondrion dye. Fluorescence is also generated when the plateletparticles in the test sample solution pass through the detection area,and the fluorescence detector is configured to detect the fluorescencegenerated by the platelet particles to obtain a third detection result,thereby identifying the platelet particles based on the first detectionresult and the third detection result.

In an embodiment, the blood cell analyzer further comprises a seconddetector and a fluorescence detector; correspondingly, the methodfurther comprises: performing fluorescence staining treatment on theplatelet particles in the test sample solution; further generatingfluorescence when the platelet particles in the test sample solutionpass through the detection area; configuring the second detector toperform light intensity detection on the scattered light which forms anangle within a preset angle range with the propagation direction of thelaser beam to obtain a second detection result, wherein the preset anglerange may be 60° to 120°; configuring the fluorescence detector todetect the fluorescence generated by the platelet particles to obtain athird detection result; identifying the platelet particles and obtainingwhite blood cell count and classification based on the first detectionresult, the second detection result and the third detection result.

By applying the above-mentioned embodiments of the present disclosure,the reflected light generated when the laser beam propagates in theoptical path can be commendably isolated such that the laser can stablyoutput a laser beam, thereby avoiding small pulses occurring due topower peaks generated when the reflected light enters the laser, andalso avoiding confusion between the interfering small pulses and thesmall pulses generated by platelet particles when the blood cells to betested are platelets, and greatly improving the detection precision ofthe blood cell analyzer.

The optical detection system in the embodiments of the presentdisclosure comprises an optical subsystem, a flow chamber and a firstdetector, and the optical subsystem comprises a laser, a front opticalassembly comprising an optical isolator, and a rear optical assemblycomprising a blocking diaphragm, wherein the laser is configured to emita laser beam; the front optical assembly is configured to perform frontoptical treatment such that the laser beam subjected to the frontoptical treatment is converged at the blocking diaphragm in a seconddirection and is converged at the blood cell sample to be tested at theblocking diaphragm in a first direction, and scattered light is thusgenerated; the rear optical assembly is disposed downstream of the flowchamber along the propagation direction of the laser beam, and isconfigured to perform rear optical treatment on the scattered light,such that the scattered light subjected to the rear optical treatmententers the first detector for light intensity detection; and the opticalisolator is configured to isolate reflected light that is generated whenthe laser beam passes through the flow chamber and the rear opticalassembly. Thus, the reflected light generated when the laser beampropagates in the optical path can be commendably isolated such that thelaser can stably output a laser beam, thereby avoiding small pulsesoccurring due to power peaks generated when the reflected light entersthe laser, and also avoiding confusion between the interfering smallpulses and the small pulses generated by platelet particles when theblood cells to be tested are platelets, and greatly improving thedetection precision of the blood cell analyzer.

The contents described above are only some specific embodiments of thepresent disclosure, but the protection scope of the present disclosureis not limited thereto. Any modifications or replacements, which can beeasily obtained by one skilled in the art within the technical scopedisclosed by the present disclosure, should fall within the protectionscope of the present disclosure. Therefore, the protection scope of thepresent disclosure depends on the protection scope of the claims.

The invention claimed is:
 1. An optical detection system, comprising anoptical subsystem, a flow chamber and a first detector; the opticalsubsystem comprising a laser, a front optical assembly and a rearoptical assembly, and the front optical assembly comprising an opticalisolator, wherein: the laser is configured to emit a laser beam; thefront optical assembly is configured to perform front optical treatmenton the laser beam, and the laser beam subjected to the front opticaltreatment is converged at a plurality of platelet particles in the flowchamber in a first direction, and scattered light is thus generated; therear optical assembly is disposed downstream of the flow chamber along apropagation direction of the laser beam, and is configured to performrear optical treatment on the scattered light, so that the scatteredlight subjected to the rear optical treatment enters the first detectorfor light intensity detection, to obtain a detection resultcorresponding to the plurality of platelet particles; and the opticalisolator is configured to isolate reflected light from the laser,wherein the reflected light is generated when the laser beam passesthrough the flow chamber, wherein the optical isolator comprises a beamsplitter prism and a polarization conversion element which areadhesively connected with each other; the beam splitter prism isconfigured to reflect an S-polarization component of an incident laserbeam and transmit a P-polarization component of the incident laser beam;and the polarization conversion element is configured to change apolarization state of the P-polarization component transmitted throughthe beam splitter prism so that the P-polarization component is changedfrom linearly polarized light into circularly polarized light, as wellas to change a polarization state of the circularly polarized lightafter reflection into S-polarized light so that the S-polarized light isreflected by the beam splitter prism; or the optical isolator comprisesa polarization analyzer and a polarization conversion element which areadhesively connected with each other; the polarization analyzer isconfigured to allow only a P-polarization component of the laser beam topass through; and the polarization conversion element is configured tochange a polarization state of the P-polarization component passingthrough the polarization analyzer so that the P-polarization componentis changed from linearly polarized light into circularly polarizedlight, as well as to change a polarization state of reflected light ofthe circularly polarized light into S-polarized light so that theS-polarized light is isolated by the polarization analyzer.
 2. Theoptical detection system of claim 1, wherein the polarization conversionelement is one of the following: a quarter wave plate and amagneto-optical crystal.
 3. The optical detection system of claim 1,wherein, when the laser beam is incident at an angle of zero withrelative to a direction of a polarization axis of the optical isolator,a reflectivity of a first incident surface of the beam splitter prism isnot greater than 0.5%.
 4. The optical detection system of claim 3,wherein the reflectivity of the first incident surface of the beamsplitter prism is not greater than 0.1%.
 5. The optical detection systemof claim 3, wherein the reflectivity of the first incident surface ofthe beam splitter prism is not greater than 0.05%.
 6. The opticaldetection system of claim 1, wherein the front optical assembly furthercomprises a collimating lens; and the collimating lens is disposedbetween the laser and the optical isolator along the propagationdirection of the laser beam and is configured to collimate the laserbeam to make the laser beam become a parallel beam.
 7. The opticaldetection system of claim 1, wherein the rear optical assembly furthercomprises a third converging element and an aperture diaphragm; and thethird converging element is configured to perform third focusing on thescattered light so that the scattered light is converged at the aperturediaphragm and enters the first detector via an aperture of the aperturediaphragm.
 8. The optical detection system of claim 1, wherein anincluded angle between the propagation direction of the laser beam and alight incident surface of the flow chamber is a non-perpendicular angle.9. The optical detection system of claim 1, wherein the laser beam has awavelength in a range of 630 nm to 640 nm.
 10. The optical detectionsystem of claim 1, wherein the laser beam is P-linearly polarized light.11. An optical detection system, comprising an optical subsystem, a flowchamber and a first detector; the optical subsystem comprising a laser,a front optical assembly and a rear optical assembly, and the frontoptical assembly comprising an optical isolator, wherein: the laser isconfigured to emit a laser beam; the front optical assembly isconfigured to perform front optical treatment on the laser beam, and thelaser beam subjected to the front optical treatment is converged at aplurality of platelet particles in the flow chamber in a firstdirection, and scattered light is thus generated; the rear opticalassembly is disposed downstream of the flow chamber along a propagationdirection of the laser beam, and is configured to perform rear opticaltreatment on the scattered light, so that the scattered light subjectedto the rear optical treatment enters the first detector for lightintensity detection, to obtain a detection result corresponding to theplurality of platelet particles; and the optical isolator is configuredto isolate reflected light from the laser, wherein the reflected lightis generated when the laser beam passes through the flow chamber;wherein the optical isolator comprises a bandpass filter and afrequency-doubling crystal which are adhesively connected with eachother; the bandpass filter is configured to allow the laser beam with awavelength λ to pass through; and the frequency-doubling crystal isconfigured to perform frequency doubling on the laser beam passingthrough the bandpass filter and perform frequency doubling again onreflected light of the frequency-doubled laser beam, so that thereflected light is filtered out by the bandpass filter.
 12. An opticaldetection system, comprising an optical subsystem, a flow chamber and afirst detector; the optical subsystem comprising a laser, a frontoptical assembly and a rear optical assembly, and the front opticalassembly comprising an optical isolator, wherein: the laser isconfigured to emit a laser beam; the front optical assembly isconfigured to perform front optical treatment on the laser beam, and thelaser beam subjected to the front optical treatment is converged at aplurality of platelet particles in the flow chamber in a firstdirection, and scattered light is thus generated; the rear opticalassembly is disposed downstream of the flow chamber along a propagationdirection of the laser beam, and is configured to perform rear opticaltreatment on the scattered light, so that the scattered light subjectedto the rear optical treatment enters the first detector for lightintensity detection, to obtain a detection result corresponding to theplurality of platelet particles; and the optical isolator is configuredto isolate reflected light from the laser, wherein the reflected lightis generated when the laser beam passes through the flow chamber,wherein the rear optical assembly further comprises a blockingdiaphragm; and the front optical assembly is further configured toperform front optical treatment on the laser beam so that the laser beamsubjected to the front optical treatment is converged at the blockingdiaphragm in a second direction.
 13. The optical detection system ofclaim 12, wherein the front optical assembly further comprises a firstlight converging element and a second light converging element; thefirst light converging element is configured to perform first focusingon the laser beam so that the laser beam is converged at the blockingdiaphragm included by the rear optical assembly in the second direction;and the second light converging element is configured to perform secondfocusing on the laser beam so that the laser beam is converged at theplurality of platelet particles in the flow chamber in the firstdirection, and scattered light is generated.
 14. The optical detectionsystem of claim 12, wherein the blocking diaphragm has a lightcollection angle of 1-10°.
 15. An optical detection system, comprisingan optical subsystem, a flow chamber and a first detector; the opticalsubsystem comprising a laser, a front optical assembly and a rearoptical assembly, and the front optical assembly comprising an opticalisolator, wherein: the laser is configured to emit a laser beam; thefront optical assembly is configured to perform front optical treatmenton the laser beam, and the laser beam subjected to the front opticaltreatment is converged at a plurality of platelet particles in the flowchamber in a first direction, and scattered light is thus generated; therear optical assembly is disposed downstream of the flow chamber along apropagation direction of the laser beam, and is configured to performrear optical treatment on the scattered light, so that the scatteredlight subjected to the rear optical treatment enters the first detectorfor light intensity detection, to obtain a detection resultcorresponding to the plurality of platelet particles; and the opticalisolator is configured to isolate reflected light from the laser,wherein the reflected light is generated when the laser beam passesthrough the flow chamber; wherein the optical detection system furthercomprises a second detector and/or a fluorescence detector; the seconddetector is disposed in a direction which forms an angle within a presetangle range with the propagation direction of the laser beam, and isconfigured to perform light intensity detection on the scattered lightwhich forms an angle within the preset angle range with the propagationdirection of the laser beam; and the fluorescence detector is disposedin a direction which forms an angle within a preset angle range with thepropagation direction of the laser beam, and is configured to performfluorescence detection on fluorescence generated by the plurality ofplatelet particles.
 16. An optical detection system, comprising anoptical subsystem, a flow chamber and a first detector; the opticalsubsystem comprising a laser, a front optical assembly and a rearoptical assembly, and the front optical assembly comprising an opticalisolator, wherein: the laser is configured to emit a laser beam; thefront optical assembly is configured to perform front optical treatmenton the laser beam, and the laser beam subjected to the front opticaltreatment is converged at a plurality of platelet particles in the flowchamber in a first direction, and scattered light is thus generated; therear optical assembly is disposed downstream of the flow chamber along apropagation direction of the laser beam, and is configured to performrear optical treatment on the scattered light, so that the scatteredlight subjected to the rear optical treatment enters the first detectorfor light intensity detection, to obtain a detection resultcorresponding to the plurality of platelet particles; and the opticalisolator is configured to isolate reflected light from the laser,wherein the reflected light is generated when the laser beam passesthrough the flow chamber; wherein the optical isolator has an opticalisolation degree not smaller than 30 db.